Craniofacial surgery is generally performed to treat congenital deformities of the face and facial skeleton, to treat traumatic injury, or to address cosmetic or aesthetic concerns of the patient. Skilled surgeons can enhance or reconstruct the facial skeleton using biocompatible implants that are disposed beneath the facial musculature and applied to or attached to the facial skeleton (typically using screw fasteners). For example, craniofacial surgery and biomaterials can be used to create new facial skeletal contours. See, for example, ATLAS OF FACIAL IMPLANTS (Elsevier, 2007) by Michael J. Yaremchuk, MD, the disclosure of which is incorporated herein by reference in its entirety. Unlike the use of injected liquid materials, that are meant to inflate the soft tissue envelope, the use of solid facial implants can mimic the facial appearance obtained with more extensive facial skeletal surgeries that require cutting and repositioning of facial bone. The facial implants are typically provided in a limited number of basic shapes, that can be carved and shaped by the surgeon at the time of implant.
Facial implants are conventionally made from silicone rubber or sintered porous plastics (such as polyethylene) that are molded into predetermined shapes, depending on the area of the face to be treated. See, for example, U.S. Pat. No. 6,551,608, the disclosure of which is incorporated herein by reference in its entirety. For each area, a family of implants of varying size and similar contour are often provided. This is required, so that the facial implants can be readily customized to suit both the underlying skeletal contours and the overlying facial tissue, in order to give the desired final appearance, without excessive sculpting of the implant by the surgeon during the implant procedure.
Problems can exist, however, due to the relatively large size of some of the implants (e.g., requiring more extensive surgical access to the area to be augmented) and/or the amount of customization and associated time required, due to the limited selection of implants in each family. In general, temporary size implants are often used intraoperatively to determine which implant shape might be appropriate, which requires a large inventory of implants to be available to the surgeon. Implants which are not optimal for the specific needs of the patient can sometime be used. Implants of different sizes must be custom carved and, in extreme cases, stacked and joined together by sutures if standard implants are not ideal for specific clinical situations. Alternatively, a shim can be custom cut and inserted underneath the implant and affixed thereto by protuberances and adhesive, as described in U.S. Pat. No. 5,514,179, the disclosure of which is incorporated herein by reference in its entirely. Current techniques can be inefficient and imprecise, and intraoperative constructs might be unstable in shape, leading to unpredictable outcomes. Further, the outcome can be less than ideal when the surgeon commits to opening an implant that, after placement, is less than ideal in projection.
The precise positioning of facial implants by the surgeon during the implant procedure is often difficult and time consuming, due to limited exposure of the areas to be augmented. Craniofacial implants are typically placed through remote access incisions to avoid visible scarring on the overlying soft tissue envelope and creation of suture lines directly over the implant which can predispose to wound breakdown, implant exposure and hence, surgical failure. Accurate implant placement is especially difficult when attempting to place a pair of implants symmetrically. For example, symmetric placement of facial implants can be problematic due to the complex three-dimension surface of the facial skeleton and limited surgical exposure.
In addition, placement of facial implants requires exposure (i.e., removal of overlying attached soft tissues) of the skeletal area to be augmented. Further, the implant needs to be held in proper position while it is being secured to the underlying bone, typically with screws. Available conventional clamps (e.g., tissue forceps, bone reduction forceps, towel clips, etc.) do not provide stable purchase of the implant and bone, due to their purchase end design, the dimensions of the purchasing end, and the configuration and orientation of the purchasing end. Inadvertent movement of the implant while it is being secured can result in implant malposition and, if recognized intraoperatively, the need to remove and reposition the implant.